21052120 has 64 divisors (see below), whose sum is σ = 50893920. Its totient is φ = 7809024.

The previous prime is 21052117. The next prime is 21052121. The reversal of 21052120 is 2125012.

It is a self number, because there is not a number n which added to its sum of digits gives 21052120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21052121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56254 + ... + 56626.

Almost surely, 2^21052120 is an apocalyptic number.

21052120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21052120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25446960).

21052120 is an abundant number, since it is smaller than the sum of its proper divisors (29841800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21052120 is a wasteful number, since it uses less digits than its factorization.

21052120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484 (or 480 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21052120 is about 4588.2589290492. The cubic root of 21052120 is about 276.1204753046.

Adding to 21052120 its reverse (2125012), we get a palindrome (23177132).

It can be divided in two parts, 2105 and 2120, that added together give a square (4225 = 65²).

The spelling of 21052120 in words is "twenty-one million, fifty-two thousand, one hundred twenty".